Hot air sealing apparatus for cartons

ABSTRACT

Apparatus for forming and heat sealing a flat cardboard carton blank, die cut to proper size and shape and crease scored to provide the proper lines at which forming is to take place. The inside of the blank is coated with a non-toxic coating of thermoplastic material which will bond to cardboard when liquified by heat and put under pressure. Hot air guns in the form of vertically extending cylinders are pivotally mounted at each side of the forming run of the blank for movement toward and from the forming run. Fluid pressure cylinders and pistons are provided to move the hot air guns away from the forming run when a blank is not present at the forming run, when the blanks become jammed in the apparatus and when the apparatus is turned off. The hot air guns support nozzle assemblies at their lower ends in the form of ducts extending over the end panels of the blanks and having auxiliary ducts extending upwardly along the sealing tabs of the blanks. These ducts have nozzle openings therein for supplying hot air to the insides of the end panels to liquify the thermoplastic coating and to spot heat the sealing tabs. When the end panels and sealing tabs are heated, a forming block moves into the center of the blank and forms the carton to form and applies pressure to the sealing tabs and end panels to seal the blank to carton form.

United States Patent [19] Talbot et al.

[ Jan. 15, 1974 HOT AIR SEALING APPARATUS F0 CARTONS [7 3] Assignee: Peters Machinery Company,

Chicago, Ill.

[22] Filed: Nov. 10, 1972 [21] Appl.. No.: 305,353

[52] US. Cl. 93/41, 93/49 AC, 93/51 R, 93/DIG. l [51] Int. Cl B3lb 3/60, B3lb l/44, B3lb 1/64 [58] Field of Search 93/DIG. l, 36 R, 93/36 PC, 36 MM, 41, 49 R, 49 AC, 51 R, 53 R, 53 AC [56] References Cited UNITED STATES PATENTS 3,056,337 10/1962 Bahr et al. 93/51 R 3,421,416 I l/l969 Benzon-Petersen 93/41 X 3,041,943 7/1962 Turner 93/41 3,331,293 7/1967 Mullaney 93/DIG. 1 2,678,679 5/1954 Bergstcin 93/DIG. 1 2,928,220 3/1960 Kannengiesser et a1, 93/DlG. 1 2,978,008 4/1961 Conti 93/DIG. 1

Primary Examiner-Andrew R. Juhasz Assistant Examiner-James F. Coan Att0meyBenjamin H. Sherman et a1.

[57] i A ABSTRACT Apparatus for forming and heat sealing a flat cardboard carton blank, die cut to proper size and shape and crease scored to provide the proper lines at which forming is to take place. The inside of the blank is coated with a non-toxic coating of thermoplastic ma terial which will bond to cardboard when liquified by heat and put under pressure. Hot air guns in the form of vertically extending cylinders are pivotally mounted at each side of the forming run of the blank for movement toward and from the forming run. Fluid pressure cylinders and pistons are provided to move the hot air guns away from the forming run when a blank is not present at the forming run, when the blanks become jammed in the apparatus and when the apparatus is turned off. The hot air guns support nozzle assemblies at their lower ends in the form of ducts extending over the end panels of the blanks and having auxiliary ducts extending upwardly along the sealing tabs of the blanks. These ducts have nozzle openings therein for supplying hot air to the insides of the end panels to liquify the thermoplastic coating and to spot heat the sealing tabs. When the end panels and sealing tabs are heated, a forming block moves into the center of the blank and forms the carton to form and applies pressure to the sealing tabs and end panels to seal the blank to carton form.

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HOT AIR SEALING APPARATUS FOR CARTONS FIELD OF THE INVENTION I-Iot air sealing apparatus for carton forming machines.

BACKGROUND, SUMMARY AND ADVANTAGES OF INVENTION Heretofore, flat cardboard carton blanks, die cut to the required size and shape and crease scored to provide folding lines have been fed out of a magazine, one blank at a time and moved longitudinally through the machine with the blanks in a horizontal flat position. Such machines are shown and described in US. Pat. No. 3,056,337 dated Oct. 2, 1962 and in US. Pat. No. 3,327,680 dated June 27, 1967 and assigned to the assignee of the present invention. The blanks are usually stacked in a magazine and fed by shuttle or kicker type feed and picked off the magazine by vacuum, depositing the blanks onto a reciprocating transport which pushes the carton blank through the machine. With such. carton forming machines, the means for sealing, the mating surfaces of the blanks as formed has been a liquid polyvinyl adhesive or a polyethylene based hot melt adhesive. While such carton forming machines and adhesives have been satisfactory and are in common use today, where such adhesives are used, provision must be made for storing the glue, the machine itself must be provided with glue pots and the machine cannot be started up until the glue is melted, which requires a substantial amount of time. Moreover, with such machines there is always the possibility of spillage of the glue particularly when adding to the glue pots and a substantial amount of time is required for setting of the glue.

In accordance with the principles of the present invention, the preformed blanks may be fed from a magazine through a forming station as in U.S. Pat. Nos. 3,056,337 and 3,327,680 and the sides of the blanks, which will be the inside of the carton are coated with a non-toxic thermoplastic material which melts when heated and firmly adheres to the mating surfaces of the carton in a very short time interval under very little pressure. In the sealing process of the present invention, heated air is ejected from nozzles, contacting the insides of the end flaps of the carton blank prior to forming, and the nozzles are withdrawn when cartons are not fed from the magazine due to stoppage of jamming upstream of the carton former. The air from the nozzles which would ordinarily come in close contact with the forming block and pressure rolls of the forming station would raise the temperature of these parts above the melting point of the thermoplastic material coating inside of the carton, and keep the temperature of these parts at such a heat that upon stopping of a carton forming operation and resumption of the feeding and forming operation, the first carton formed around the forming block would absorb sufficient heat from the block and the carton to melt the plastic coating and stick to the forming block and prevent removal of the formed, sealed carton from the forming block. In order to prevent this, the forming block has been water cooled to maintain the block at a temperature below that of the melting point of the thermoplastic material laminated to the inside of the carton board. Such cooling systems are expensive, difficult to maintain and, if not properly maintained, where the forming block is subject to heat for long intervals of time, will be ineffective to prevent sticking of the carton blanks to the block.

In accordance with the principles of the present invention, the hot air nozzles are moved away from the forming parts so that the heated air will not impinge upon the forming block or related forming parts by carrying the nozzles on the lower ends of heat guns heating the air as it passes therealong and pivoted along opposite sides of the forming run for movement about parallel axes extending longitudinally of travel of a carton through the machine. Each heat gun is pivoted away from the forming block by individual fluid pressure operated cylinders which maintain the air gun and nozzles in position to direct air away from the forming block and forming parts, upon shut off of the carton feed, an interruption in the feed of cartons, or an emergency stop of the machine due to a carton jam or when jogging the cartons through the machine.

The advantages of the present invention, therefore, are that where a grease resistant inner coating is required, this coating may be a non-toxic adhesive heated by air bonding the carton parts and thereby reducing the cost of operation of the machine.

Another advantage of the present invention over conventional hot melt sealing operations is that no time is required for premelting of the glue prior to operation of the machine.

A further advantage is that glue pots are required and the storing of glue and adding of glue to the glue pots is eliminated.

A still further advantage of the invention is that a strong, effective seal is attained in a minimum amount of time and at reduced pressures and the coating is not visible or detrimentalto the appearance of the carton.

A further advantage of the invention is that the heat activated coating provides an instant bond with a resultant rigid formed carton.

Other objects, features and advantages of the invention will be readily apparent from the following description of a preferred embodiment thereof, taken in conjunction with the accompanying drawings, although variations and modifications may be effected without departing from the spirit and scope of the novel concepts of the disclosure.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagrammatic view in side elevation of a carton forming and heat sealing apparatus constructed in accordance with the principles of the present invention.

FIG. 2 is a fragmentary sectional view taken substantially along line II-II of FIG. 1 showing the heat cylinders and nozzles and their mounting, and also showing the forming block in side elevation.

FIG. 3 is a horizontal sectional view taken substantially along line III-III of FIG. 2.

FIG. 4 is a diagrammatic plan view looking down on the sealing and forming station of the machine, with certain parts removed.

FIG. 5 is a fragmentary sectional view taken substantially along line V--V of FIG. 4.

FIG. 6 is a diagrammatic fragmentary sectional view taken substantially along line VIVI of FIG. 5.

FIG. 7 is an enlarged sectional view taken through one of the heat sealing nozzle assemblies with certain parts broken away.

FIG. 8 is a view of a typical carton blank showing the sealing tabs in upright position and the end panels extending horizontally and diagrammatically illustrating the impingement of hot air on the end panels as passing beneath the sealing nozzles.

FIG. 9 is a diagrammatic view showing the hot air guns and nozzles with a schematic control for retaining the nozzles in the operative position shown and moving said nozzles away from the forming run when the machine is not in operation or a carton blank is not in position in the forming run.

FIG. 10 is a vertical sectional view taken through one of the hot air guns.

FIG. 11 is a view illustrating the steps of forming a precut and scored blank into the form of a carton in accordance with the principles of the present invention; and

FIGS. 12, 13, 14 and 15 are views illustrating the suc-' cessive steps of holding the sealing tabs upwardly, supplying hot air to the end panels of the carton and sealing tabs and forming the blank to carton form.

DESCRIPTION OF PREFERRED EMBODIMENT OF INVENTION In FIG. 1 of the drawings, we have diagrammatically shown a form of carton forming and sealing apparatus forming the carton blank on the general principles of those shown and described in U.S. Pat. No. 3,056,337 dated Oct. 2, 1962 and assigned to the assignee of the present invention. The detailed structure of the apparatus, therefore, need not be repeated herein. The apparatus generally includes a magazine and carton feeding station 11 supporting a stack of preformed and scored carton blanks 12, slit to form end tabs 13, sealing tabs 14 and 15 on opposite sides of the end tabs and a cover 16.

The inside of the carton blank is coated or laminated with a non-toxic thermoplastic material such as a polyethylene film or Saran (polyvinylidene) having the properties of bonding to the paper board of the carton when liquified by heat and put under pressure, and having the properties of being resistant to the absorption of grease, low permeability to the transfer of air and moisture, and non-toxic in contact with food products.

It should be understood, however, that where it may not be desired to coat the inside of the carton blank with a thermoplastic material, a preapplied hot melt adhesive can be pattern printed on the preselected surfaces of the carton blank by the blank manufacture, which adhesive is non-adhesive in its cooled state but is reactivated or liquified at an elevated temperature, to which it is subjected when in contact with heated air from air nozzles.

The carton blank feeding, folding and forming stations of the apparatus operate on principles similar to those disclosed in U.S. Pat. No. 3,056,337, so need not herein be shown or described except where necessary to render our present invention readily understandable.

The machine generally includes a main frame 17 having a table top 19 along which the carton blanks are advanced for folding the sealing flaps upwardly and holding the end flaps down as advanced to a sealing and forming station 21.

The advancing of the carton blanks may be like that shown and described in U.S. Pat. No. 3,056,337, so need not herein be shown or described further, except insofar as it is necessary to make the present invention readily understandable.

Vacuum cups (not shown) may remove the bottom carton blank of the stack of carton blanks 12 one by one and successively place the carton blanks on the table top 19 to be advanced therealong by feeders 22, which may be reciprocating feeders as in U.S. Pat. No. 3,056,337 and diagrammatically illustrated in block form by broken lines in FIG. 4. The carton blank is advanced along the table top 19 with a cover 16 leading the carton blank. The feeders 22 may be reciprocating feeders engaging the trailing end of the blank and feeding the blank along the table top 19 in a manner well known to those skilled in the art so not herein shown or described.

As the blank is advanced to the sealing and forming station 21, it passes beneath hold-down rollers 23 and along and beneath a former 24. Forming fingers 25,25 are spaced along opposite sides of the former 24 distances equal to the longitudinal spacing of the sealing tabs 14 and 15 and extend beneath said tabs. The forming fingers 25 are pivoted upwardly and inwardly to fold tabs along the former 24 and retain the tabs thereto. The forming fingers 25,25 are adjustably mounted on longitudinally extending bars (not shown) driven in timed relation with respect to passage of the carton blanks along the table top 19 to fold the sealing tabs along the inclined surfaces of the former each time a carton blank comes into registry with said fingers. The manner of operating the forming fingers and the structure of said fingers is known to those skilled in the art and is no part of the present invention so need not herein be shown or described further.

From the former 24 the carton blanks are advanced to the sealing and forming station 21 shown in FIGS. 4,5,6 and 7. The fonning station 21 includes a pair of parallel spaced bars 27 having upwardly inclined flared advance ends 29 engaging along the outsides of the sealing tabs 14 and 15 and retaining said sealing tabs in generally vertical positions to pass along the outsides of hot air nozzle assemblies 30 extending along the forming station as shown in FIGS. 2,4 and 5, directing hot air to the end panels of the carton blank and to the outside of the sealing tabs 14 and 15 to melt the laminated coating on the insides of the end panels and preheat the outsides of the sealing tabs as will hereinafter more clearly appear as this specification proceeds.

Each nozzle assembly 30 is mounted on the lower end of a generally cylindrical hot air gun 31. The hot air gun 31 is pivoted intermediate its ends to a support plate 32 slidably guided between vertically spaced bars 33 extending between vertically extending posts 35 for adjustment therealong. The bars 33 are mounted on and extend upwardly of opposite sides of the table top 19. Clamping levers 36 pivoted to the plates 32 are threaded in strips 36a clamping said plates in position between said bars 33 upon tightening of said strips in engagement with said bars, or to release said plates for slidable adjustable movement along said bars (FIG. 3).

The means for moving the nozzle assemblies 30 away from the forming station when carton blanks are not present at the forming station comprise individual fluid pressure operated cylinders 39 having pistons 40 therein and piston rods 41 extending from the lower or piston rod ends of said cylinders. The cylinders 39 are trunnioned between cars 42 extending inwardly of upright bracket plates 43 mounted on and secured to the plates 32 for adjustable movement therewith upon adjustment of said plates along the bars 33. Trunnion pins 44 trunnion the head ends of said cylinders between the cars 42, to accommodate movement thereof upon movement of the nozzle assemblies 30 toward and from the forming run. The piston rods 41 have connectors 45 at their lower ends pivotally connected to the outer ends of crank arms 46 on pivot pins 47. The inner ends of the crank arms 46 are keyed or otherwise secured to pivot shafts 48 extending from clamping blocks 49. As shown in FIG. 3, the hot air guns 31 are each supported between a pair of clamping blocks 49 and 50, clamped to said hot air guns as by clamping screws 51. Each clamping block 49 has a shaft 48 extending therefrom through bearing blocks 53 carried on opposite sides of the plate 32.

In FIG. 10, the heat gun 31 is shown as consisting of two concentric heat-resistant stainless steel cylinders or tubes. An outer cylinder 54 forms a casing for the heat gun and has an inner cylinder or tube 55 containing a ceramic core 56 along which extend electrical resistance heater elements 57 properly sized and wound to provide heat sufficient to raise the temperature of air passing over the element tothe necessary temperature to melt the inside coating of the end panels of the carton blank. The temperature of the air ejected from the nozzle assemblies may be of the order of 800F. Conductors 58, connected with a source of electric power, are connected with said heater elements 57 to energize said heater elements. Said conductors enter the hot air gun through a junction box 59, abutting a radial flange 60 extending from the top of the outer cylinder 54 and closing the upper end of said cylinder. The top of the junction box has a sealing tube 61 extending therethrough and nuts 62 threaded on opposite ends of said sealing tube to insulate said conductors 58 from the hot air gun and to prevent the passage of air into the gun along said conductors.

As shown in FIG. 10, the inner cylinder or tube 55 is shorter than the outer cylinder 54 to accommodate the air forced into the outer cylinder through an inlet 63 to pass upwardly in the space between the two cylinders and then pass downwardly along the resistance heaters 57, for discharge through an outlet 65. Said outlet 65 extends through a base 66 for the inner and outer cylinders 54 and 55. The base 66 is shown as being in three parts and includes a central part 67 cross-drilled to accommodate the insertion of a thermometer 69 therein, to indicate the temperature of the air passing to the nozzle assemblies 30. The intermediate part 67 of the base 66 is shown as being mounted on abutting plates 70 having an outlet passageway 71 leading therethrough concentric with the passageway 65 and communicating with a duct 72 suitably mounted on the bottom plate 70 and extending therefrom.

The duct 72 forms a support for and has communication with a nozzle assembly 30, as shown in FIGS. 6 and 7. The nozzle assembly 30 includes an inner nozzle section 73 within which the duct 72 extends and is supplied with hot air through an opening 74 having communication with the inner nozzle section 73. The inner nozzle section 73 has a flat bottom 75 having a plurality of nozzle openings 76 leading therethrough, on each side of the center thereof. The nozzle openings 76 are so positioned as to direct hot air to the inside opposite end portions of an associated end panel 13, as shown in FIG. 8.

The nozzle 30 also has an advance nozzle section 77 having an upright wall 79 having a nozzle opening 80 leading therethrough. Air is supplied to the advance nozzle section 77 through an outlet opening 81 in the duct 72. The nozzle opening 80 is positioned to direct hot air on the outer surface of a sealing tab to heat said tab and prevent chilling of the mating liquified thermoplastic surfaces, and thereby preventing a poor bond between the surfaces.

The nozzle assembly 30 also has a nozzle section 83 disposed on the opposite side of the nozzle section 73 from the advance nozzle section 76 and having an up right wall 84 having a nozzle opening 85 leading therethrough, for directing hot air on the adjacent sealing tab 15 as a carton blank is progressed to the forming station as diagrammatically shown in FIG. 8.

Extending along the bottom of the nozzle sections 77 and 73 is a retainer bar 87 having an inwardly opening guide slot 88 extending therealong. The guide slot 88 has a flared bottom portion 89 coverging toward the plane of the table top 19 and forming a support and guide for the end panels 13 of the carton blanks as shown in FIG. 5. The guide slot 88 is open at the top in the area of the nozzle opening 76 to hold the end panel flat and accommodate the impinging of hot air thereon through the nozzle openings 76.

The retainer bars 27 are spaced inwardly of side walls 26 of the forming section and extend along each side of the table and are adjustably mounted on the side walls 26 on support plates 91 for adjustable movement toward and from the center of the table top in accordance with the width of the carton to be formed and sealed. Said retainer bars extend over the end panels and serve to hole the sealing tabs up as the carbon blank passes to the forming and sealing station.

The guide or retainer bars 27 terminate adjacent inclined advance faces 93 of the advance nozzle sections 77 and retain the sealing tabs of the carton blank to come along the insides of the upright walls of the nozzle sections 77 for the impingement of hot air on the sealing tabs 14, as the cover engages a stop 95 extending across the table top 19.

As shown in FIG. 6, the nozzle sections 77,73 and 83 extend over and beyond opposite sides of a forming well 96 defined by parallel walls 97 extending downwardly from the table top 19 and shown as forming continuations thereof. The walls 97 have right angled upper end portions secured to the main frame of the machine with their top surfaces on a level with the top of the table top 19. Brackets 99 depend from the bottom of the table top 19 on the outer sides of the walls 97 and form supports for parallel shafts 100 spaced from opposite ends of the well 96. Pressure rollers 101 are journalled on said shafts on anti-friction bearings 103. The brackets 99 have slots 104 therein for the shafts 100. Each shaft 100 has a socket 106 therein adjacent each end thereof for compression springs 107. The opposite ends of said springs are seated in seating members 109 engaged by adjustment screws 111, threaded in the brackets 99, for adjusting the positions of said rollers relative to the well 96 and the sealing force exerted on the carton as pushed downwardly along said rollers by a forming block 112. A back-up screw 113 threaded in the opposite side of the bracket 99 from the spring 107 and in alignment with the adjustment screw 111. Said back-up screw is seated in a suitable socket formed in the shaft 100 to limit movement of said shaft relative to the carton blank and former 12, to avoid excessive pressures on the blank. It is, of course, understood that adjustment screws and back-up screws are provided for each end of each shaft 100, to give the rollers 101 a uniform sealing pressure throughout their length.

The former 112 is shown as being a conventional rectangular block or mandrel vertically movable within the well 96 to fold the side walls of the carton upwardly and fold the end panels 13 upwardly along the outsides of the sealing tabs, to come into engagement with the outer surfaces of the sealing tabs 14 and 15 and form the carton to form. During this forming operation, the pressure rollers 101 exert sufficient pressure on the end panels to seal said end panels to the selaing tabs as the carton passes thereby. The forming block or mandrel will thus eject the carton blank from the bottom of the well onto a conveyor (now shown) carrying the formed carton through a discharge opening 115 opening through the side walls of the machine frame. The carton will then be fully formed, with the cover extending upright to be filled with suitable articles in a conventional manner.

The forming block or mandrel 112 is mounted on the lower end ofa bar 116 herein shown as being rectangular in cross section and having an actuating arm 117 pivotally connected thereto in a manner not shown herein since it forms no part of the present invention. The actuating arm 117 is pivoted at its opposite end in a bracket member 118 spaced above the table top 19 on a pivot pin 119 and reciprocably moved back and forth through a suitable mechanism which may be a crank and link mechanism (not shown), operating on principles similar to which the forming mandrel of U.S. Pat. No. 3,056,337 is moved up and down.

As shown in FIG. 5, the forming block 112 has a guide plate 120 extending upwardly from the top thereof along its forward side and suitably secured thereto. The guide plate 120 comes along the inside of the cover 16 of the carton and retains the cover in an upright position as the carton is being formed by downward movement of the forming block along the well 96.

In FIGS. 11 to 15, the steps of forming the carton from a scored and slit carton blank are generally shown. In these figures, a carton blank 12 is picked off the bottom ofa stack of blanks by vacuum and the folding fingers 25 prefold the sealing tabs about the former 24. As the carton blank passes to the sealing and forming station, the forming bars 27 retain the sealing tabs in their inwardly inclined position as shown in FIG. 12 amd cooperate with the inclined ends of the advance nozzles 77 to raise the tabs to conform to the upright faces of said advance nozzles. The sealing tabs held in generally upright positions are then impinged with hot air in spots as the end panels are impinged with hot air along opposite end portions thereof, to melt the plastic covering on the inside of the panel and heat the outsides of the sealing tabs. At this time, the forming block comes down and engages the central portion of the carton blank having the end panels projecting therefrom and moves the blank downwardly into the well 96, pressure being exerted on the end panels and sealing tabs during this operation by the pressure rollers 101, coacting with the forming block moving the carton blank downwardly into its completed form with its cover extending upwardly-The formed carton shown in FIG. 11 is then ejected from the apparatus for filling.

In FIG. 9, we have diagrammatically shown a simplified control system for moving the nozzle assemblies 30 into the operating position shown for a sealing operation and out of the way of the forming station out of contact with the forming block and forming parts when a carton blank is not at the forming station, due to jamming, lack of carbon blanks or stopping the machine. As shown in this figure, we have shown a blower 121 driven by a motor 122 and having ducts 123 leading therefrom having connection with the air inlet 63 at the bottoms of the hot air guns 31 for supplying air under pressure thereto to be heated by the resistance heaters 57, as the air passes upwardly in the space between the tubes 54 and 55 and downwardly along the inner tube 55 through the nozzle assembly. The motor 122 may be started and stopped through a suitable electric control system (not shown) upon the turning on" or of of a blower switch (not shown) in the electrical control system.

A Solenoid operated valve 125 is shown as being connected with a source of fluid under pressure, which may be air, through a pressure supply line 126. The valve 125 has a pressure line 127 leading therefrom connected with a pressure line 129 supplying air under pressure to the piston rod ends of the cylinders 39, to swing the nozzles 30 away from the forming station by retractable movement of the piston rods 41 within the cylinders 39, and pivotal movement of the air guns about the axes of the shafts 48. The valve 125 also has a pressure line 130 leading therefrom connected with a pressure line 131 having connection with the head ends of the cylinders 39 to swing the hot air guns 31 and nozzles 30 into the sealing position shown for a sealing operation when a carton is present in the forming station.

The valve 125 may be biased by a spring 133 into position to admit fluid under pressure through the pressures lines 127 and 129 when said valve is deenergized, to assure that the nozzles will be out of operative association with the forming station when the solenoid (not shown) for operating said valve is deenergized.

The electrical control system for energizing and deenergizing the solenoid coil of the solenoid controlled valve 125 and controlling the positions of the air guns, is diagrammatically shown in block form and includes a control box 135 connected with the source of power through power lines 136 and 137. The control box may be a conventional control box containing the controls for picking the cartons from the magazine and feeding the cartons through the forming run for operating the forming block energizing the motor for driving the blower for supplying air to the heat guns, and energizing the resistance heaters of the heat guns and the electrical parts of the other operative parts of the machine. The control and connections from the control box to the blower motor and resistance heaters, however, need not herein be shown since they form no part of the present invention. The control box includes a jog switch button 138, an on switch button 139 and an off" switch button 140. The on and off and switch buttons operate conventional switches for turning the circuit on and of or for jogging a carton blank into position, so a detailed description thereof need not be required for the present invention. A double conductor cable 141 leads from the control box to a feed sensor 142 to energize a double conductor cable 143 leading from the feed sensor to a time delay relay 144. The time delay relay is energized upon closing of the circuits (not shown) of the feed sensor, sensing the feeding of a carton through the machine and closes its contacts immediately upon energization thereof to energize the solenoid valve 125 through a double conductor 146. This moves the valve 125 into position to supply air to the head ends of the cylinders 39 and bring the air nozzles 30 into operating position to apply heated air to the carton panels. This occurs before the carton being fed reaches the air nozzles. Upon deenergization of the time delay relay, a pre-set adjustable time delay will take place, allowing sufficient time for cartons in transit to pass completely through the machine, before deenergization of the solenoid valve and retraction of the nozzle assemblies into their inoperative positions.

A jam sensor 149 is also in the line 138 in series with the feed sensor and time delay relay. The jam sensor serves to deenergize the solenoid for the solenoid operated valve 125 upon jamming of the cartons, by opening the circuit from said sensor to the solenoid (not shown) for operating the solenoid controlled valve 125. This will effect the supply of fluid under pressure to the pressure lines 127 and 129 and to the piston rod ends of the cylinders 39 and move the nozzles 30 away from the forming station.

In the form of the invention shown, the heat guns 31 and air nozzle assemblies 30 will be moved out of operating position into a position such that the heated air is directed away from the forming block and forming parts which contact the carton during the forming operation when the feed of cartons is shut off, the of switch 140 is in an of position, the jam sensor is open due to a carton jam, or at any time the system is deenergized by a power failure.

The time delay relay 144, however, energizes the solenoid of the solenoid controlled valve 125 immediately upon closing of the start button 139. This causes the cylinders 39 to bring the air nozzles 30 into operating position to apply heated air to the carton panels, and occurs before the carton being fed reaches the air nozzles. The time delay relay also delays the energization of the solenoid coil (not shown) for operating the solenoid control valve for a pre-set adjustable time d'elay, allowing sufficient time for cartons in transit to pass completely through the machine and be formed and sealed before the contacts open to deenergize the solenoid coil (not shown), operating the solenoid controlled valve 125, and cause the air nozzles to retract into their operative positions.

It may be seen from the foregoing that a simple sealing system for carton blanks has been provided for sealing the blanks to carton form by the use of heated air ejected from nozzles to liquify a plastic coating on the inside of the carton or end flaps of the carton. The sealing system is so operative that when cartons are not fed from the magazine due to a stoppage of jamming upstream of the carton former, the air from the nozzles will be directed away from the carton former and other forming parts to avoid raising the temperature of the former and forming parts above the melting point of the thermoplastic material coating the inside of the carton.

It may further be seen that the sealing apparatus just described avoids all gluing operations, makes it unnecessary to water cool the forming block by assuring that the heated air will not impinge upon the forming parts upon a stoppage in the feed of cartons through the machine and the lack of a carton blank in the forming station.

We claim as our invention:

1. In a hot air carton sealing and forming apparatus for sealing carton blanks having a non-toxic coating on the inner surface thereof having the property of bond ing to other surfaces when liquified and put under pressure,

a sealing and forming station including an air cylinder at each side of said station,

nozzles on the lower ends of said air cylinders,

means supplying air to said cylinders,

other means heating the air ejection through said nozzles to certain preselected portions of the carton blank,

and means moving said nozzles to direct air away from the sealing and forming station when a carton blank is not present at the station.

2. The carton sealing and forming apparatus of claim 1, including means mounting said air cylinders for movement about axes extending longitudinally of travel of the carton blanks, to accommodate movement of said nozzles away from the sealing and forming station, and

other means moving said nozzles toward the sealing and forming station when a carton blank is in position for heating and sealing.

3. The carton sealing and forming apparatus of claim 1, wherein means are provided for normally holding said air cylinders and nozzles out of heating relation relative to the sealing and forming station of the apparatus, and for moving said air cylinders and nozzles in inwardly extended relation with respect to the sealing and forming station to direct heated air on the flaps of the cartons passing thereby when the apparatus is turned to a run position and a carton blank is present at the sealing and forming station.

4. The carton sealing and forming apparatus of claim 3, including a time delay relay causing said cylinders and nozzles to remain in operative association with a carton blank until all of the cartons have cleared the sealing and forming station.

5. The carton sealing and forming apparatus of claim 4, including a jam sensor effecting movement of said cylinders and nozzles outwardly of the blanks in the sealing and forming station upon jamming of the cartons.

6. The carton sealing and forming apparatus of claim 5, including a feed sensor sensing the feed of cartons to the sealing and forming station and effecting movement of said air cylinders and nozzles away from the carton blank when no carton is present at the sealing and forming station.

7. The carton sealing and forming apparatus of claim wherein the air cylinders are pivoted intermediate their ends for movement about parallel axes extending in the direction of feed of cartons through the apparatus, and

wherein individual fluid pressure cylinders and pistons are provided to move said air culinders and nozzles in outwardly extended relation with respect to the sealing and forming station when a carton is not present at said station.

8. The carton sealing and forming apparatus of claim 7, including a supporting framework extending transversely of the apparatus,

means supporting said air cylinders and said fluid pressure operated cylinder and piston means on said framework for lateral adjustable movement to conform to the carton blanks being formed and sealed, and

clamping means clamping said air cylinders and fluid pressure operated cylinders and pistons in selected positions along said framework.

9. The carton sealing and forming apparatus of claim 7, wherein the connections from said cylinders and pistons to said hot air cylinders include piston rods extensibly and retractably movable relative to said fluid pressure cylinders, and cranks pivoted to the ends of said piston rods and secured to said air cylinders coaxial with the pivots thereof, for pivoting said nozzles toward and from the forming run of apparatus.

10. The carton sealing and forming apparatus of claim 2,

wherein the carton blank is scored and slit to provide oppositely disposed end panels and sealing tabs on opposite sides of said end panels, and

wherein the nozzles are each provided with a downwardly opening nozzle surface having a plurality of nozzle openings leading through each end thereof for directing hot air on the end panels and are each provided with an air chamber on each side of said downwardly opening nozzles, each having an upright wall having a nozzle opening leading therethrough fo spot heating upwardly turned sealing tabs of the carton blank prior to forming and sealing said sealing tabs to said end panels.

11. The carton sealing and forming apparatus of claim 10, wherein said nozzles are patterned to supply a large volume of hot air to said end panels adjacent each end portion thereof on the inside of the carton blank and to supply a small volume of air for spot heating said sealing tabs on the outsides thereof.

12. The carton sealing and forming apparatus of claim 11, including a forming well extending beneath the path of travel of cartons and between said nozzles,

a forming block engaging the carton blank and moving the carton blank along said forming well to form the blank to carton form with the end panels and sealing tabs in permanently sealed relation with respect to each other.

13. The carton sealing and forming apparatus of claim 12, including pressure rollers at opposite sides of said forming well and exerting pressure on the sealing tabs and end panels as moved downwardly along said forming well.

14. A carton sealing and forming apparatus for forming and sealing cartons from flat blanks having end panels and sealing tabs on opposite sides of said end panels and scored to form said tabs and to accommodate shaping of the blank to carton form, in which the blank has a non-toxic plastic coating on the inner surface thereof having the properties of bonding when liquified by heat and put under pressure, comprising,

a sealing and forming station,

means advancing a blank to the sealing and forming station and pivoting the sealing tabs upwardly and holding the end tabs flat during such advance,

a heat applying nozzle supported at each side of the sealing and forming station for movement toward and from the forming station and directed to apply hot air under pressure to said end panels along the insides thereof, and to heat said sealing tabs along the outsides thereof,

a forming block vertically movable to engage and form the blank to carton form, and effect sealing of the sealing tabs to the end panels, and

power means moving said nozzles away from said sealing and forming station to direct the hot air out of contact with the forming parts and prevent heating thereof, when no carton blank is present at the forming station.

15. The carton sealing and forming apparatus of claim 14, wherein the nozzles each include a nozzle duct assembly having a hot air inlet leading thereinto and having a flat bottom surface having a plurality of nozzle openings leading therefrom and having auxiliary nozzle ducts on opposite sides of said nozzle ducts, each having a vertically extending wall having at least one nozzle opening leading therethrough, to impinge hot air on the outsides of the sealing tabs.

16. The apparatus of claim 15, wherein guide shoes having slots therein are mounted at the incoming ends of said nozzle ducts for holding the end panels flat to come beneath the flat bottom surface of said nozzle ducts and having plows disposed in advance thereof for guiding the sealing tabs to pass along the vertically extending walls of the auxiliary nozzle ducts in upright positions.

17. The carton sealing and forming apparatus of claim 16,

wherein the hot air inlet to each nozzle duct assembly includes a vertical cylinder suspending said nozzle duct assembly from its lower end, electric heating means within said cylinder, and means supplying air to said cylinder and forcing hot air therefrom through said nozzle duct assembly, and

wherein each cylinder is pivotally mounted intermediate its ends for movement about axes extending longitudinally of the sealing and forming station and power means are provided for moving said cylinders and nozzle duct assemblies toward and from the forming run, and assuring said nozzle duct assemblies will direct hot air away from the forming run when the apparatus is turned off, when no carton blank is present in the forming run and when the carton blanks become jammed.

18. The apparatus of claim 17, wherein the power means comprise individual fluid pressure cylinders and pistons, and connections between said pistons to said hot air cylinders for pivoting said hot air cylinders towards and from said sealing and forming station upon movement of said pistons therealong.

19. The apparatus of claim 18, including control means effecting retraction of said hot air cylinders and nozzle assemblies from the sealing and forming station including a feed sensor sensing the movement of carton blanks to the sealing and forming station,

a jam sensor sensing the jamming of a carton blank,

and

a time delay relay delaying the supply of fluid under pressure to said cylinders to bring said nozzles out of operating position to apply heated air to the carton blanks until a carton blank in the sealing and forming station has cleared said station, and been ejected in form of a sealed carton.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 78.5, 255 Dated J n y gg Richard G. Talbot; Edward Rose; and Robert A. Roth It is certified that error appears in the aboveidentified patent and that saidLetters Patent are hereby corrected as shown below:

,, Column 2, line 29, insert --notbefore ["required";

Column' 7, line 2, change "12" to --l12---;"

line 15, correct spellingof "sealing'k line 18, change "now" to "not";

Column 9, line 17, change "138" 1:6 -148"; 1 line 57, change "of" to --or Column 10, line 64, correct spellingvof "cylinders".

s ned and sealed this 27th day' of August 1974;

(SEAL Attest MCCOY M! QQ c. MARSHALL DANN Attesting Officer Commissioner of Patents.

uscoMM-oc wan-pea fi US. GOVERNMENT PRINTING OFFICE "(I'D-366d,

1 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent Nb. r 3,785, 55 Dated J nu ry 15, 19 4 IQQn Richard C. Talbot; Edward Rose; and Robert A. Both It is certified that error appears in the aboveidentified patent and that said Letters Patent are hereby corrected as shown below:

Column 2, line 29, insert -not-- before "required";

Column 7, line 2, change "12" to --l l2--;f line 15, correct spellingof se.a1ing";* line 18, change "now" to --not-;

Column 9, line 17, change "138" w l48---; line 57, change "of" to --or- Column 10, line 64, correct spellingof "Cylinders". Y

Signed" and sealed this 27th day of August 1974.

(SEAL Attest:

MCCOY I T c. MARSHALL DANN testing Officer Commissioner of Patents FORM 0-1050 (IO-69) 

1. In a hot air carton sealing and forming apparatus for sealing carton blanks having a non-toxic coating on the inner surface thereof having the property of bonding to other surfaces when liquified and put under pressure, a sealing and forming station including an air cylinder at each side of said station, nozzles on the lower ends of said air cylinders, means supplying air to said cylinders, other means heating the air ejection through said nozzles to certain preselected portions of the carton blank, and means moving said nozzles to direct air away from the sealing and forming station when a carton blank is not present at the station.
 2. The carton sealing and forming apparatus of claim 1, including means mounting said air cylinders for movement about axes extending longitudinally of travel of the carton blanks, to accommodate movement of said nozzles away from the sealing and forming station, and other means moving said nozzles toward the sealing and forming station when a carton blank is in position for heating and sealing.
 3. The carton sealing and forming apparatus of claim 1, wherein means are provided for normally holding said air cylinders and nozzles out of heating relation relative to the sealing and forming station of the apparatus, and for moving said air cylinders and nozzles in inwardly extended relation with respect to the sealing and forming station to direct heated air on the flaps of the cartons passing thereby when the apparatus is turned to a ''''run'''' position and a carton blank is present at the sealing and forming station.
 4. The carton sealing and forming apparatus of claim 3, including a time delay relay causing said cylinders and nozzles to remain in operative association with a carton blank until all of the cartons have cleared the sealing and forming station.
 5. The carton sealing and forming apparatus of claim 4, including a jam sensor effecting movement of said cylinders and nozzles outwardly of the blanks in the sealing and forming station upon jamming of the cartons.
 6. The carton sealing and forming apparatus of claim 5, including a feed sensor sensing the feed of cartons to the sealing and forming station and effecting movement of said air cylinders and nozzles away from the carton blank when no carton is present at the sealing and forming station.
 7. The carton sealing and forming apparatus of claim 3, wherein the air cylinders are pivoted intermediate their ends for movement about parallel axes extending in the direction of feed of cartons through the apparatus, and wherein individual fluid pressure cylinders and pistons are provided to move said air culinders and nozzles in outwardly extended relation with respect to the sealing and foRming station when a carton is not present at said station.
 8. The carton sealing and forming apparatus of claim 7, including a supporting framework extending transversely of the apparatus, means supporting said air cylinders and said fluid pressure operated cylinder and piston means on said framework for lateral adjustable movement to conform to the carton blanks being formed and sealed, and clamping means clamping said air cylinders and fluid pressure operated cylinders and pistons in selected positions along said framework.
 9. The carton sealing and forming apparatus of claim 7, wherein the connections from said cylinders and pistons to said hot air cylinders include piston rods extensibly and retractably movable relative to said fluid pressure cylinders, and cranks pivoted to the ends of said piston rods and secured to said air cylinders coaxial with the pivots thereof, for pivoting said nozzles toward and from the forming run of apparatus.
 10. The carton sealing and forming apparatus of claim 2, wherein the carton blank is scored and slit to provide oppositely disposed end panels and sealing tabs on opposite sides of said end panels, and wherein the nozzles are each provided with a downwardly opening nozzle surface having a plurality of nozzle openings leading through each end thereof for directing hot air on the end panels and are each provided with an air chamber on each side of said downwardly opening nozzles, each having an upright wall having a nozzle opening leading therethrough fo spot heating upwardly turned sealing tabs of the carton blank prior to forming and sealing said sealing tabs to said end panels.
 11. The carton sealing and forming apparatus of claim 10, wherein said nozzles are patterned to supply a large volume of hot air to said end panels adjacent each end portion thereof on the inside of the carton blank and to supply a small volume of air for spot heating said sealing tabs on the outsides thereof.
 12. The carton sealing and forming apparatus of claim 11, including a forming well extending beneath the path of travel of cartons and between said nozzles, a forming block engaging the carton blank and moving the carton blank along said forming well to form the blank to carton form with the end panels and sealing tabs in permanently sealed relation with respect to each other.
 13. The carton sealing and forming apparatus of claim 12, including pressure rollers at opposite sides of said forming well and exerting pressure on the sealing tabs and end panels as moved downwardly along said forming well.
 14. A carton sealing and forming apparatus for forming and sealing cartons from flat blanks having end panels and sealing tabs on opposite sides of said end panels and scored to form said tabs and to accommodate shaping of the blank to carton form, in which the blank has a non-toxic plastic coating on the inner surface thereof having the properties of bonding when liquified by heat and put under pressure, comprising, a sealing and forming station, means advancing a blank to the sealing and forming station and pivoting the sealing tabs upwardly and holding the end tabs flat during such advance, a heat applying nozzle supported at each side of the sealing and forming station for movement toward and from the forming station and directed to apply hot air under pressure to said end panels along the insides thereof, and to heat said sealing tabs along the outsides thereof, a forming block vertically movable to engage and form the blank to carton form, and effect sealing of the sealing tabs to the end panels, and power means moving said nozzles away from said sealing and forming station to direct the hot air out of contact with the forming parts and prevent heating thereof, when no carton blank is present at the forming station.
 15. The carton sealing and forming apparatus of claim 14, wherein the nozzles each include a nozzle duct assembly having a hot air inlet leading thereinto and having a flat bottom surface having a plurality of nozzle openings leading therefrom and having auxiliary nozzle ducts on opposite sides of said nozzle ducts, each having a vertically extending wall having at least one nozzle opening leading therethrough, to impinge hot air on the outsides of the sealing tabs.
 16. The apparatus of claim 15, wherein guide shoes having slots therein are mounted at the incoming ends of said nozzle ducts for holding the end panels flat to come beneath the flat bottom surface of said nozzle ducts and having plows disposed in advance thereof for guiding the sealing tabs to pass along the vertically extending walls of the auxiliary nozzle ducts in upright positions.
 17. The carton sealing and forming apparatus of claim 16, wherein the hot air inlet to each nozzle duct assembly includes a vertical cylinder suspending said nozzle duct assembly from its lower end, electric heating means within said cylinder, and means supplying air to said cylinder and forcing hot air therefrom through said nozzle duct assembly, and wherein each cylinder is pivotally mounted intermediate its ends for movement about axes extending longitudinally of the sealing and forming station and power means are provided for moving said cylinders and nozzle duct assemblies toward and from the forming run, and assuring said nozzle duct assemblies will direct hot air away from the forming run when the apparatus is turned off, when no carton blank is present in the forming run and when the carton blanks become jammed.
 18. The apparatus of claim 17, wherein the power means comprise individual fluid pressure cylinders and pistons, and connections between said pistons to said hot air cylinders for pivoting said hot air cylinders towards and from said sealing and forming station upon movement of said pistons therealong.
 19. The apparatus of claim 18, including control means effecting retraction of said hot air cylinders and nozzle assemblies from the sealing and forming station including a feed sensor sensing the movement of carton blanks to the sealing and forming station, a jam sensor sensing the jamming of a carton blank, and a time delay relay delaying the supply of fluid under pressure to said cylinders to bring said nozzles out of operating position to apply heated air to the carton blanks until a carton blank in the sealing and forming station has cleared said station, and been ejected in form of a sealed carton. 